Method, nozzle and device for atomizing active substances contained in a fiquid

ABSTRACT

A method for atomizing active substances contained in a liquid, where: the method uses electrohydrodynamic means with at least one nozzle and at least one electrode, the nozzle and the electrode being formed and/or arranged in such a way and a voltage that is applied to the electrode being selected in such a way that a molecularization of the active substances contained in the liquid takes place and parasitic effects and/or disturbing influences that occur during the atomization, and in particular production of ozone, are reduced to the greatest extent. A nozzle for use in the method, where: an outer capillary tube of nonconducting material and an electrode in wire form arranged in the capillary tube, wherein the capillary tube and/or the electrode are formed and/or arranged in such a way that, during operation of the nozzle and atomization of the active substances contained in the liquid, the electrode is constantly wetted and no oxygen from the ambient air has contact with the surface of the electrode. A device for atomizing active substances contained in a liquid, where: a first, outer nozzle, inside which a second, inner nozzle is arranged, and means for producing an air stream in the first, outer nozzle, so that a liquid atomized by the inner nozzle is discharged into the ambience from the outer nozzle, it being possible for the device to interact with a device for separating a space into an active-substance area.

The present invention relates to a method, a nozzle and a device for atomizing active substances contained in a liquid, comprising electrohydrodynamic means, wherein parasitic effects and/or disturbing influences, and in particular production of ozone, are reduced to the greatest extent. When electrohydrodynamic means are mentioned here, this is intended to refer to means that use an electric field and make use of the electrospray effect.

Methods, nozzles and devices for producing a finely divided spray from a liquid comprising electrohydrodynamic means are known, for example, from EP 0 671 980 B1, a detailed overview of the prior art on which the present invention is based being given in the introductory part of the cited document. However, the conventional methods, nozzles and devices for atomizing active substances contained in a liquid have the disadvantage that parasitic effects, such as for example undesired charges or undesired reactions, occur during the atomization and, in particular, there is undesired production of ozone. The conventional methods, nozzles and devices can therefore only be used to a restricted extent, and in particular are not suitable for application in the pharmaceutical sector, for example for atomizing a pharmaceutical active substance for inhalation.

FIG. 1 a shows a schematic representation of the atomization of a liquid from a metallic electrically conducting nozzle using electrohydrodynamic means and FIG. 1 b shows the field lines when a voltage is applied to the dry nozzle from FIG. 1 a, the same field being applied to the dry nozzle as that which is applied to the nozzle filled with liquid from FIG. 1 a. However, in particular when high voltages are used and when large amounts of liquid are atomized, the atomization of a liquid according to FIGS. 1 a and b causes an electric field with field lines as are obtained by superimposing FIGS. 1 a and b, and consequently causes undesired ozone production according to the reaction

½O2(g)→UV/HV→O(g)→O2→O3(g),

in particular at the edges of the electrically conducting tube of the nozzle that are in contact with oxygen from the surrounding air.

Such methods and devices are therefore not suitable in particular in enclosed spaces, and in particular for administering pharmaceutical active substances for purposes of inhalation.

Also known from the prior art are vaporizing devices, a liquid being vaporized by means of heat, but with the fine distribution of active substances contained in the liquid usually only being very incomplete, and also the hot water vapour that is produced, together with the associated increase in the humidity and temperature, having disturbing effects that disadvantageously overlie the actually intended effect of delivering active substances. Furthermore, in such vaporization there is disadvantageously no molecularization of the active substances contained in the liquid.

The object of the present invention is therefore to provide a method, a nozzle and a device for atomizing a liquid with active substances contained in the liquid, wherein the disadvantages of the prior art are overcome and, in particular, parasitic effects and/or disturbing influences that occur during the atomization, and in particular production of ozone, are reduced to the greatest extent.

The object is achieved by the features of the claims. Without constituting any restriction, advantageous embodiments of the present invention are mentioned in the subclaims and/or the following description, which is accompanied by schematic drawings, in which:

FIG. 1 a shows a schematic representation of the atomization of a liquid from a metallic electrically conducting nozzle using electrohydrodynamic means;

FIG. 1 b shows the dry nozzle from FIG. 1 a, the same field being applied to the dry nozzle as that which is applied to the nozzle filled with liquid from FIG. 1 a;

FIG. 2 a shows a schematic plan view of a nozzle according to the invention;

FIG. 2 b shows a schematic section through the nozzle from FIG. 2 a along the line A-A from FIG. 2 a;

FIG. 3 a shows the end of the nozzle from FIG. 2 b;

FIG. 3 b shows a first modification of the nozzle from FIG. 3 a;

FIG. 3 c shows a second modification of the nozzle from FIG. 3 a;

FIG. 4 shows a schematic enlarged joint representation of the nozzles from FIGS. 3 a, 3 b and 3 c with a liquid in the nozzle and an atomized liquid emerging from the nozzle during the operation of the nozzle;

FIG. 5 a shows a schematic plan view of a device according to the invention from above;

FIG. 5 b shows a schematic section through the device from FIG. 5 a along the line A-A from FIG. 5 a; and

FIG. 6 shows a further schematic representation of a device according to the invention from FIG. 5; and

FIG. 7 shows a further greatly schematized representation of a device according to the invention.

According to a first fundamental idea of the present invention, the invention comprises a method for atomizing active substances contained in a liquid comprising electrohydrodynamic means with at least one nozzle at least one electrode, the nozzle and the electrode being formed and/or arranged in such a way, and also a flow rate of the liquid to be atomized in the nozzle being selected in such a way, and also a voltage that is applied to the electrode being selected in such a way that a molecularization of the active substances contained in the liquid takes place and parasitic effects and/or disturbing influences that occur during the atomization, and in particular production of ozone, are reduced to the greatest extent.

For this, a flow rate of the liquid to be atomized in the nozzle of 0.001 to 0.010 μl per second and advantageously in the range of 0.002 to 0.005 μl per second, is used, and also a voltage of at most 3.5 kV, and advantageously a voltage in the range of approximately 1-2.5 kV, is used in a suitable way.

This is so because the inventors of the present invention have found that the undesired ozone production in the prior art is attributable in particular to an excessively high voltage being used and also to the use of a nozzle with a conductive tube, ozone being produced in accordance with the following formula when the tube is used as an electrode and/or there is contact of the electrode with the ambient air and a high voltage is used:

½O2(g)→UV/HV→O(g)→O2→O3(g)

Therefore, the method according to the invention advantageously uses in particular a voltage range within which the aforementioned reaction does not occur and transports the liquid to be atomized in the nozzle at a flow rate which is sufficiently low for the said voltage to be adequate to atomize the liquid in a molecularizing manner.

A nozzle according to the invention for use in the method according to the invention comprises in particular an outer capillary tube of nonconducting material and an electrode in wire form arranged in the capillary tube, wherein the capillary tube and/or the electrode are formed and/or arranged in such a way that, during operation of the nozzle and atomization of the active substances contained in the liquid, the electrode is constantly wetted and no oxygen from the ambient air has contact with the surface of the electrode, and in particular also no contact with the tip or edge of the electrode from which the field lines of the applied electric field emanate during the atomization.

When mention is made here of a capillary tube, this is intended to mean a tube that can also have capillary properties, so that the liquid flows in the tube by means of its capillarity alone, the tube also advantageously being able to interact with other means for transporting the liquid.

The electrode is therefore advantageously arranged inside the capillary tube of the nozzle and the capillary tube is also formed in such a way that the liquid from a liquid reservoir which is in communication with the capillary tube constantly wets the interior of the tube and the electrode, and in particular also the end of the electrode, on account of the capillary properties of the capillary tube, and/or at least constantly wets them during the operation of the nozzle, so that in each case no oxygen from the air comes into contact with the electrode.

A suitable geometry of a nonconducting capillary tube according to the invention that is suitable for this purpose, with an electrode lying on the inside, comprises a capillary tube and an electrode of which the ends respectively lie approximately on one level.

The end of the capillary tube may also advantageously protrude slightly beyond the end of the electrode, thereby ensuring that the end of the electrode is constantly wetted on account of the capillary properties of the capillary tube. The end of the electrode may also suitably protrude from the capillary tube 10 by a small predetermined amount, the predetermined amount being selected in such a way that, during the operation of the nozzle, by using the electrospray effect and applying a predetermined small voltage according to the invention to the electrode, the end of the electrode is completely wetted and is arranged within a Taylor cone that forms.

This ensures that the end of the electrode does not have any contact with oxygen from the ambient air during the operation of the nozzle.

The capillary tube of a nozzle according to the invention also suitably has an inside diameter of 50 μm to 1000 μm and advantageously of 100 μm to 500 μm and still more advantageously of approximately 150 μm and the capillary tube also suitably has a wall thickness of 1 μm to 20 μm and advantageously of approximately 10 μm, and the electrode suitably has a diameter of 1 μm to 100 μm and advantageously of approximately 50 μm. The above advantageous geometries and dimensions according to the invention are advantageously combined with the flow rate according to the invention of the liquid to be atomized in the nozzle and the low voltage according to the invention, so that complete molecularization takes place during the operation of the nozzle with electrohydrodynamic means and parasitic effects and/or disturbing influences, and in particular production of ozone, are reduced to the greatest extent during the atomization.

The nonconducting capillary tube according to the invention of a nozzle according to the invention is suitably made of a nonconducting plastic and the electrode is made of a conductive material, in each case also with resistance on contact with aggressive media.

A device according to the invention for atomizing active substances contained in a liquid comprises in particular a first, outer nozzle, inside which a second, inner nozzle is arranged, and also means for producing an air stream in the first, outer nozzle, so that a liquid atomized by the inner nozzle is discharged into the ambience from the outer nozzle.

If the method and arrangement according to the invention of a nozzle according to the invention are used in a device according to the invention, the atomized active substances originating from the inner nozzle in a molecularized form are effectively discharged into the ambience by means of the outer nozzle. The device according to the invention is suitable in particular for an inner nozzle according to the invention, which molecularizes virtually completely a liquid transported in the nozzle with a very low flow rate and using electrohydrodynamic means with a very low voltage, while avoiding parasitic effects and in particular while avoiding ozone production.

A second electrode, which interacts with the first electrode arranged inside the first nozzle according to the invention, may also be suitably provided on the outer nozzle of a device according to the invention.

A device according to the invention may also suitably comprise a pump for transporting the liquid to be atomized into the nozzle, and also comprises a suitable voltage generator.

The pump is suitably formed in such a way that it interacts with the capillary tube and operates at a pumping rate in such a way that the liquid flows in the capillary tube with the aforementioned flow rate according to the invention, the capillary tube acting as a throttle of the pump.

The method according to the invention, the nozzle according to the invention and the device according to the invention are suitable in particular for atomizing fragrances, odour removers, pharmaceutical agents, medical agents, biologically active agents and disinfectants.

The use of the method, the nozzle and the device according to the invention in the pharmaceutical sector or for delivering fragrances is particularly advantageous, since pharmaceutical active substances for inhalation purposes or biologically active agents or fragrances in particular can be administered via the ambient air of a room in a particularly mild way, for example for inhalation purposes.

A device according to the invention with its advantageously low expulsion rate of very pure active substances can interact in permanent or periodic operation, particularly advantageously in the pharmaceutical sector for the ozone-free administration of active substances to be inhaled, with a device for separating a room into an interior area with active substances contained in the air and an exterior area, it being possible for the device to be arranged inside the interior area or its nozzle to be in communication with the interior area.

The present invention is described in detail below with reference to the schematic drawings.

FIG. 2 a shows a schematic plan view of a nozzle 1 according to the invention, comprising an outer capillary tube 10 inside which a first electrode 11 is arranged, and FIG. 2 b shows a schematic section through the nozzle 1 from FIG. 2 a along line A-A from FIG. 2 a. According to the invention, the capillary tube 10 of the nozzle 1 is made of a nonconducting material and may for example be made of plastic, for example of PC, PMMA, PUR, PI, etc. and may advantageously be made of a material with resistance to aggressive media, for example of PI, PEAK, PTFE, PP, PE, PET, PPSU, PPS or PVDF, etc. The electrode 11 is suitably likewise made of a material with material resistance to aggressive media and according to the invention is arranged inside the capillary tube 10 in such a way that, at least during the operation of the nozzle 1 and the atomization of active substances contained in the liquid F, the electrode 11 is constantly wetted and no oxygen from the ambient air has contact with the surface of the electrode 11. On account of the capillary properties of the tube 10, the end E1 of the electrode 11 can lie approximately on a level with the end E0 of the capillary tube 10, as schematically represented in FIG. 2 b and FIG. 3 a.

When mention is made here of capillary properties, this is intended to mean capillary properties that may also be suitable for the liquid to flow in the tube by means of its capillarity alone, the tube also advantageously being able to interact with other means for transporting the liquid.

The electrode 11 may suitably be arranged centrally inside the capillary tube 10, but may also be arranged decentrally and even at an edge of the tube 10, as long as it is ensured that, during the operation of the nozzle 1, the electrode 11 is constantly wetted and no oxygen from the ambient air has contact with the surface of the electrode 11. The electrode 11 may suitably be a thin wire, which may be arranged inside the tube 10 in any way desired, as long as it does not significantly hinder a pumping flow and/or capillary flow of a liquid F inside the tube 10.

FIG. 3 a shows a partial detail of the end of a nozzle 1 according to the invention from FIG. 2 b, and FIGS. 3 b and 3 c show modifications of the nozzle 1 from FIG. 3 a. The end E1′ of the electrode 11 from FIG. 3 b protrudes from the capillary tube 10 by a predetermined amount, the predetermined amount being selected according to the invention in such a way that, during the operation of the nozzle 1, by using the electrospray effect and applying a predetermined voltage to the electrode 11, the end E1 of the electrode 11 is completely wetted and is arranged within a Taylor cone that forms, as described below on the basis of FIG. 4.

FIG. 3 c shows a further modification of the nozzle according to the invention from FIG. 3 a, the end E1′ of the electrode 11 being arranged inside the tube 10 and the end E0 of the capillary tube 10 protruding by a predetermined small amount beyond the end E1 of the electrode 11. This ensures that, on account of the capillary properties of the capillary tube 10, the end E1′ of the electrode 11 is constantly wetted and no oxygen from the ambient air has contact with the surface of the electrode 11.

FIG. 4 shows an enlarged partial section of a nozzle 1 according to the invention during the operation of the nozzle 1 and the atomization of a liquid F by means of hydrodynamic means, a Taylor cone K of liquid initially forming above the end of the electrode 11, followed by a liquid jet S, which is then followed by molecularization of the liquid F with the active substances contained in it and the formation of a mist N of active substance. The nozzles 1 according to the invention from FIGS. 3 a, 3 b and 3 c are schematically represented one above the other in FIG. 4.

As previously stated with respect to FIG. 2, the electrode 11 may be suitably arranged centrally inside the tube 10 and also be arranged decentrally, the Taylor cone in each case being displaced correspondingly with the arrangement of the electrode 11, and the end E1, E1′ of the electrode 11 being constantly wetted, at least during the operation of the nozzle 1.

A nozzle 1 according to the invention for the operation of the method according to the invention for atomizing active substances contained in a liquid F with a sufficiently low voltage and a sufficiently low flow rate of the liquid F to be atomized in the nozzle 1, with a voltage of at most 3.5 kV and advantageously in the range of approximately 1 to 2.5 kV and with a flow rate in the range of 0.001 to 0.10 μl per second and advantageously in the range of 0.002 to 0.005 μl per second, suitably has very small dimensions. Accordingly, a capillary tube of a nozzle according to the invention also suitably has an inside diameter of 50 μm to 1000 μm and advantageously of 100 μm to 500 μm and still more advantageously of approximately 150 μm and the capillary tube also suitably has a wall thickness of 1 μm to 20 μm and advantageously of approximately 10 μm, and the electrode suitably has a diameter of 1 μm to 100 μm and advantageously of approximately 50 μm.

FIG. 5 a shows a schematic plan view of a device 3 according to the invention for atomizing active substances contained in a liquid F, comprising an outer nozzle 2 according to the invention, arranged inside which is an inner nozzle 1 according to the invention, described above on the basis of FIGS. 2 to 4, and FIG. 5 b shows a schematic section through the device from FIG. 5 a along the line A-A from FIG. 5 a during the operation of the device 3.

The device 3 suitably comprises an outer nozzle tube 20, inside which the nozzle 1 according to the invention is arranged, and also means 22 for producing an air stream L in the outer tube 20 and for transporting the active substances atomized by the nozzle 1 out of the nozzle 20 into the ambience. The device 3 may suitably comprise a second electrode 21, which may suitably be arranged on the outer tube 20 and may be formed for example, as schematically represented in FIGS. 5 a and 5 b, as an annular electrode. It is clear that the electrode 21 may be formed in various ways, such as for example also as a grid with partial coverage of the opening of the tube 20. It is also clear that it is also possible to dispense with an outer electrode 21, and a voltage is applied to the electrode 11 in such a way that the electrode 11 interacts with a surrounding frame potential.

The means 22 for producing an air stream L in the outer nozzle 2 may, for example, be a fan or an ion wind generator.

FIG. 6 shows a further greatly schematized representation of a device 3 according to the invention as shown in FIG. 5, comprising an inner nozzle 1 according to the invention, which is suitably arranged in an outer nozzle 2, and also a schematic voltage generator 23 for applying the voltage to the electrodes 11 and 21 and a liquid reservoir 25, which is in communication with the capillary tube 10 of the inner nozzle 1, and also comprising a pump 24, which transports a liquid to be atomized according to the invention with a flow rate in the range of 0.001 to 0.010 μl per second and advantageously in the range 0.002 to 0.005 μl per second. In this case, the pump 24 may be advantageously formed and arranged in such a way, and operated with a pumping rate in such a way, that it interacts with the capillary tube 10 of the inner nozzle 1 in such a way that the capillary tube 10 acts as a throttle.

The low flow rate according to the invention, the low voltage according to the invention, the arrangement according to the invention of the first electrode 11 and the dimensions according to the invention of the capillary tube 10 and of the electrode 11 make completely molecularizing atomization of active substances contained in a liquid F possible, with reduction to the greatest extent of parasitic effects or disturbing influences and in particular with reduction to the greatest extent of disturbing ozone production and also constant production of very pure and finely divided active substances in permanent and/or periodic operation.

A device 3 according to the invention is therefore suitable in particular for the atomization of fragrances, odour removers, pharmaceutical agents, biologically active agents and disinfectants, it being possible for the device 3 to interact suitably with a device 4 which is suitable for separating a space 40 into an interior area 401 with active substances contained in the air and an exterior area 402. In this case, the device 3 according to the invention may be arranged inside the space 40, as schematically represented in FIG. 7, but it may also be arranged outside the space 401 and suitably connected to the interior space 401. The device 4 may be suitably semipermeable and/or gastight in one or both directions.

For example, the device may also be an oxygen tent or a sheet or cover for purposes of inhaling a pharmaceutical active substance administered by way of the respiratory tracts, for which the present invention is particularly suited, since it makes it possible for active substances to be produced in an ozone-free molecularizing manner and also, unlike in the case of the prior art, makes it possible for active substance to be fed into a predetermined space in a mild, uniform and regular way and in amounts that can be metered very accurately, without disturbing influences on the humidity and temperature in the room.

It is also clear that a device 3 according to the invention is also particularly suitable for enriching any desired space continuously with a highly pure and finely divided active substance. 

1. Method for atomizing active substances contained in a liquid (F), where: the method uses electrohydrodynamic means with at least one electrically nonconducting nozzle (1) and at least one electrode (11) arranged in the nozzle (1), the nozzle and the electrode (11) being formed and/or arranged in such a way and a flow rate of the liquid (F) to be atomized in the nozzle (1) being selected in such a way, and a voltage that is applied to the electrode (11) being selected in such a way that a molecularization of the active substances contained in the liquid (F) takes place, and parasitic effects and/or disturbing influences that occur during the atomization, and in particular production of ozone, are reduced to the greatest extent.
 2. Method according to claim 1, where: a flow rate of the liquid (F) to be atomized in the nozzle (1) in the range of 0.001 to 0.010 μl per second, and advantageously in the range of 0.002 to 0.005 μl per second, is used.
 3. Method according to claim 1, where: a voltage of at most 3.5 kV is used.
 4. Method according to claim 3, where: a voltage in the range of approximately 1 to 2.5 kV is used.
 5. Nozzle (1) for use in the method according to claim 1, comprising: an outer capillary tube (10) of nonconducting material and an electrode (11) in wire form arranged in the capillary tube (10), wherein the capillary tube (10) and/or the electrode (11) are formed and/or arranged in such a way that, during operation of the nozzle (1) and atomization of the active substances contained in the liquid (F), the electrode (11) is constantly wetted and no oxygen from the ambient air has contact with the surface of the electrode (11).
 6. Nozzle (1) according to claim 5, where: the capillary tube (10) and/or the electrode (11) are formed and/or arranged in such a way that a liquid (F) from a liquid reservoir which is in communication with the capillary tube (10) constantly wets the interior of the tube (10) and the electrode (11) on account of the capillary properties of the capillary tube (10), and/or at least constantly wets them during the operation of the nozzle (1), so that in each case no oxygen from the air comes into contact with the electrode (11).
 7. Nozzle (1) according to claim 6, where: the end (E0) of the capillary tube (10) and the end (E1) of the electrode (11) lie approximately on one level.
 8. Nozzle (1) according to claim 6, where: the end (E0) of the capillary tube (10) protrudes beyond the end (E1) of the electrode (11).
 9. Nozzle (1) according to claim 6, where: the end (E1) of the electrode (11) protrudes from the capillary tube (10) by a predetermined amount: the predetermined amount being selected in such a way that, during the operation of the nozzle (1), by using the electrospray effect and applying a predetermined voltage to the electrode (11), the end (E1) of the electrode (11) is completely wetted and is arranged within a Taylor cone that forms.
 10. Nozzle (1) according to claim 6, where: the capillary tube (10) has an inside diameter (100) of 50 μm to 1000 μm and advantageously of 100 μm to 500 μm and still more advantageously of approximately 150 μm, and the capillary tube (10) has a wall thickness (101) of 1 μm to 20 μm and advantageously of approximately 10 μm, and the electrode (11) has a diameter (110) of 1 μm to 100 μm and advantageously of approximately 50 μm.
 11. Nozzle (1) according to claim 5, where: the capillary tube (10) is made of an electrically nonconducting material and the electrode (11) is made of an electrically conductive material, in each case also with resistance on contact with aggressive media.
 12. Device (3) for atomizing active substances contained in a liquid (F), comprising: an outer nozzle (2), inside which an inner nozzle (1) according to claim 5 is arranged, and means for producing an air stream in the first, outer nozzle (2), so that a liquid (F) atomized by the inner nozzle (1) is discharged into the ambience from the outer nozzle (2).
 13. Device (3) according to claim 12, comprising a second electrode (21), which interacts with the first electrode (11) arranged in the first nozzle (1), arranged on the outer nozzle (2).
 14. Device (3) according to claim 12, comprising: a pump (24) for transporting the liquid (F) to be atomized into the nozzle (1), the pump operating with a pumping rate such that the liquid (F) is transported with a flow rate in the range of 0.001 to 0.010 μl per second and advantageously in the range of 0.002 to 0.005 μl per second, and comprising a voltage generator (23), which generates a voltage of at most 3.5 kV and advantageously a voltage in the range of 1 to 2.5 kV.
 15. Device (3) according to claim 14, wherein: the pump (24) is formed in such a way and the capillary tube (10) is formed in such a way that the pump (24) transports the liquid (F) in the nozzle (1), the capillary tube (10) acting as a throttle of the pumping rate.
 16. Use of the method according to claim 1 for atomizing fragrances, odour removers, pharmaceutical agents, biologically active agents and disinfectants.
 17. Use of the device (3) according to claim 12 together with a device (4) for separating a space (40) into an interior area (401) with active substances contained in the air and an exterior area (402).
 18. Device (4) according to claim 17, the device (4) being permeable or semipermeable or gastight in one or both directions. 